Optimization of medium-frequency transformers with large capacity and high insulation requirement

The application of traction power electronic transformers (PETs) requires high efficiency and power density, where insulation becomes a key factor in the transformer design process. This paper presents a model-based optimization design and engineering realization that considers the electromagnetic, geometric and insulating properties of the transformer. To accurately model the transformer considering the geometric asymmetry caused by high insulation requirement, a hybrid distributed inductance model is put forward. Based on the optimized pareto domain obtained by the optimization method, one can get the most suitable optimal design point of the volume and the efficiency of the transformer. A 140kW, 85kV insulation prototype has been designed and the static parameters measurement experiments and simulation results verified the theoretical design. The electricity and insulation experiments will be done in the future due to COVID-19.